Hi everyobdy- Schubert serial no 1009 here!!!! thats right 1009! The earliest in existance as far as we know right now (need edison museum to get back in touch w/ me to see what theres is!) anyways my question right now is what size/strength tension spring is possible to put in...mine as lost its tension, being closed for such a long time. I have a little stopper i invented for it that i made out of a little carpet sample square, but if its possible to swap springs i would. is it hard to get off- you need to get it off w/ lid open i think- cause its streched when closed and not when open. any advice appriciated- thanks!